1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) and, more particularly, to an LCD capable of improving an adhesive strength of a sealant by increasing an attachment area of the sealant formed between a first substrate, a thin film transistor (TFT) substrate, and a second substrate, a color filter substrate.
2. Description of the Related Art
In general, the application coverage of a liquid crystal display (LCD) extends thanks to its characteristics that it is lighter, thinner, and driven at a low power consumption. Thus, the LCD is commonly used as a means for displaying images in mobile computers, mobile phones, office automation equipment, or the like.
The LCD displays a desired image on its screen by controlling the amount of transmission of light according to a video signal applied to a plurality of control switching elements arranged in a matrix form.
The LCD includes a liquid crystal panel including a color filter substrate, an upper substrate, and a thin film transistor (TFT) substrate, a lower substrate, which face, between which and a liquid crystal layer is formed, and a driver that supplies a scan signal and image information to the liquid crystal panel to operate the liquid crystal panel.
The related art LCD having such construction will now be described with reference to the accompanying drawings.
FIG. 1 is a plan view illustrating the first substrate 1, the TFT array substrate, of the related art general LCD, and FIG. 2 is a sectional view taken along line I-I′ in FIG. 1 and showing the section of a TFT 7 formed at each pixel on the first substrate 1.
As shown in FIGS. 1 and 2, the related art general LCD includes the first substrate 1, the TFT array substrate, and a second substrate 2, the color filter substrate, and a liquid crystal layer 6 formed between the first and second substrates 1 and 2.
With reference to FIG. 1, gate lines GL and data lines DL are formed to cross vertically and horizontally on the first substrate 1, defining a plurality of pixels, and TFTs 7 are formed at each crossing of the gate lines GL and the data lines DL of each pixel.
With reference to FIG. 2, the TFT 7 includes a gate electrode 7a formed on the first substrate 1, a gate insulating layer 7b formed on the gate electrode 7a, a semiconductor layer 7c formed on the gate insulating layer 7b, and a source electrode 7d and a drain electrode 7e formed on the semiconductor layer 7c. A passivation layer 8 is formed on the source electrode 7d and the drain electrode 7e. 
The gate electrode 7a of the TFT 7 is connected with the gate line GL, the source electrode 7d is connected with the data line DL, and the drain electrode 7e is connected with the pixel electrode 9.
A color filter layer including color filters 11 corresponding to the pixels defined on the first substrate 1 is formed at a display area on the second substrate 2. Black matrixes 12 are formed at regions corresponding to the gate line GL, the data line DL and the TFT 7 of the display area AA and a region corresponding to a non-display area NA. A common electrode 4 is formed on the color filter 11 and the black matrix 12.
A common line 3 is formed at the non-display area NA on the first substrate 1 in order to supply a common voltage to the common electrode 4. The common line 3 is formed along edges of the display area AA, and may be connected with the common electrode 4 via a conducting means such as Ag dot or the like.
With reference to FIGS. 1 and 2, a sealant is formed along the edges of the display area AA) at the non-display area NA between the first and second substrates 1 and 2. The sealant 5 serves to allow the first and second substrates 1 and 2 to maintain their aligned and attached state and seal the region between the first and second substrates 1 and 2 to thereby prevent liquid crystal of the liquid crystal layer 6 from being leaked.
In the related art general LCD constructed as described above, the sealant 5 is formed to mostly overlap with the common line 3 on the first substrate 1 and the common electrode 4 on the second substrate 2 as shown in FIG. 1, and in this case, the common line 3 and the common electrode 4 are formed to be relatively smooth without any change in their level, so the sealant 5 attaching (bonding) the first and second substrates 1 and 2 cannot exert any force stronger than its intrinsic adhesive strength. Thus, if an external force (e.g., a force that pulls the first or second substrate) is applied to the first or second substrate 1 or 2, portions attached with the common line 3 or the common electrode 4 are frequently released at a certain region of the sealant 5, resulting in the leakage of the liquid crystal of the liquid crystal layer 6 to cause a defective image.